dhcpd-pools  2.28
ISC dhcpd lease usage analyser
stdbool.in.h
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1 /* Copyright (C) 2001-2003, 2006-2015 Free Software Foundation, Inc.
2  Written by Bruno Haible <haible@clisp.cons.org>, 2001.
3 
4  This program is free software; you can redistribute it and/or modify
5  it under the terms of the GNU General Public License as published by
6  the Free Software Foundation; either version 3, or (at your option)
7  any later version.
8 
9  This program is distributed in the hope that it will be useful,
10  but WITHOUT ANY WARRANTY; without even the implied warranty of
11  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  GNU General Public License for more details.
13 
14  You should have received a copy of the GNU General Public License
15  along with this program; if not, see <http://www.gnu.org/licenses/>. */
16 
17 #ifndef _GL_STDBOOL_H
18 #define _GL_STDBOOL_H
19 
20 /* ISO C 99 <stdbool.h> for platforms that lack it. */
21 
22 /* Usage suggestions:
23 
24  Programs that use <stdbool.h> should be aware of some limitations
25  and standards compliance issues.
26 
27  Standards compliance:
28 
29  - <stdbool.h> must be #included before 'bool', 'false', 'true'
30  can be used.
31 
32  - You cannot assume that sizeof (bool) == 1.
33 
34  - Programs should not undefine the macros bool, true, and false,
35  as C99 lists that as an "obsolescent feature".
36 
37  Limitations of this substitute, when used in a C89 environment:
38 
39  - <stdbool.h> must be #included before the '_Bool' type can be used.
40 
41  - You cannot assume that _Bool is a typedef; it might be a macro.
42 
43  - Bit-fields of type 'bool' are not supported. Portable code
44  should use 'unsigned int foo : 1;' rather than 'bool foo : 1;'.
45 
46  - In C99, casts and automatic conversions to '_Bool' or 'bool' are
47  performed in such a way that every nonzero value gets converted
48  to 'true', and zero gets converted to 'false'. This doesn't work
49  with this substitute. With this substitute, only the values 0 and 1
50  give the expected result when converted to _Bool' or 'bool'.
51 
52  - C99 allows the use of (_Bool)0.0 in constant expressions, but
53  this substitute cannot always provide this property.
54 
55  Also, it is suggested that programs use 'bool' rather than '_Bool';
56  this isn't required, but 'bool' is more common. */
57 
58 
59 /* 7.16. Boolean type and values */
60 
61 /* BeOS <sys/socket.h> already #defines false 0, true 1. We use the same
62  definitions below, but temporarily we have to #undef them. */
63 #if defined __BEOS__ && !defined __HAIKU__
64 # include <OS.h> /* defines bool but not _Bool */
65 # undef false
66 # undef true
67 #endif
68 
69 #ifdef __cplusplus
70 # define _Bool bool
71 # define bool bool
72 #else
73 # if defined __BEOS__ && !defined __HAIKU__
74  /* A compiler known to have 'bool'. */
75  /* If the compiler already has both 'bool' and '_Bool', we can assume they
76  are the same types. */
77 # if !@HAVE__BOOL@
78 typedef bool _Bool;
79 # endif
80 # else
81 # if !defined __GNUC__
82  /* If @HAVE__BOOL@:
83  Some HP-UX cc and AIX IBM C compiler versions have compiler bugs when
84  the built-in _Bool type is used. See
85  http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
86  http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
87  http://lists.gnu.org/archive/html/bug-coreutils/2005-10/msg00086.html
88  Similar bugs are likely with other compilers as well; this file
89  wouldn't be used if <stdbool.h> was working.
90  So we override the _Bool type.
91  If !@HAVE__BOOL@:
92  Need to define _Bool ourselves. As 'signed char' or as an enum type?
93  Use of a typedef, with SunPRO C, leads to a stupid
94  "warning: _Bool is a keyword in ISO C99".
95  Use of an enum type, with IRIX cc, leads to a stupid
96  "warning(1185): enumerated type mixed with another type".
97  Even the existence of an enum type, without a typedef,
98  "Invalid enumerator. (badenum)" with HP-UX cc on Tru64.
99  The only benefit of the enum, debuggability, is not important
100  with these compilers. So use 'signed char' and no enum. */
101 # define _Bool signed char
102 # else
103  /* With this compiler, trust the _Bool type if the compiler has it. */
104 # if !@HAVE__BOOL@
105  /* For the sake of symbolic names in gdb, define true and false as
106  enum constants, not only as macros.
107  It is tempting to write
108  typedef enum { false = 0, true = 1 } _Bool;
109  so that gdb prints values of type 'bool' symbolically. But then
110  values of type '_Bool' might promote to 'int' or 'unsigned int'
111  (see ISO C 99 6.7.2.2.(4)); however, '_Bool' must promote to 'int'
112  (see ISO C 99 6.3.1.1.(2)). So add a negative value to the
113  enum; this ensures that '_Bool' promotes to 'int'. */
114 typedef enum { _Bool_must_promote_to_int = -1, false = 0, true = 1 } _Bool;
115 # endif
116 # endif
117 # endif
118 # define bool _Bool
119 #endif
120 
121 /* The other macros must be usable in preprocessor directives. */
122 #ifdef __cplusplus
123 # define false false
124 # define true true
125 #else
126 # define false 0
127 # define true 1
128 #endif
129 
130 #define __bool_true_false_are_defined 1
131 
132 #endif /* _GL_STDBOOL_H */
#define _Bool
Definition: stdbool.in.h:101